In general, it is known practice to mount dental instruments on fixed cabinet structures, on cabinet structures secured to the dental chair and on moveable, typically caster supported, cabinets. The present invention is concerned with equipment of the mobile type.
The more usual prior practice, where a plurality of dental instruments are utilized selectively, has been to provide separate foot or hand controls therefore, or to provide switching on arrangements of a manual character in some convenient location. It has also been known to provide automatic selector means associated with the instruments themselves (Billin et al. U.S. Pat. No. 3,209,457; Pace applications Ser. No. 34,124, filed May 4, 1970, [U.S. Pat. No. 3,172,314 issued Jan. 23, 1973] and Ser. No. 55,664, filed July 17, 1970 [U.S. Pat. No. 3,673,709 issued July 4, 1972]).
Where a number of instruments are carried by a common support, it is known practice to provide the required slack in the hose connection by means of the usual ratchet lock on the hose reel; it is also known to use a fixed length of hose which is coiled helically, with a view to taking up slack without causing objectionable drag. In the prior Page applications mentioned above, clips for holding the hoses of instruments which are in use are disclosed, along with selector control valve means incorporated in the clips.